Prove tha `sin 25^0 cos 115^0 = 1/2 (sin 40^0 -1)`

sin25^(@)cos115^(@)=(1)/(2)(sin40^(@)-1)

Prove that cos65^(@)+cos115^(0)=0

Prove that :sin51^(0)+cos81^(0)=cos21^(0)

Prove that 2 (sin ^ (6) A + cos ^ (6) A) -3 (sin ^ (4) A + cos ^ (4) A) + 1 = 0

(2cos 40^0-cos 20^0)/(sin 20^0)=

Prove that (1+sin A+cos A)^(2)=2(1+sin A)(1+cos A)

Prove that (1 + sin2A) / (cos2A) = (cos A + sin A) / (cos A-sin A)

Prove that [(1-sin A-cos A)^(2)=2(1-sin A)(1-cos A)]

Prove that: (cos40^(@)+cos50^(@))/(sin40^(@)+sin50^(@))=1

Prove that (i) " sin " 80^(@) "cos " 20^(@) - " cos " 80^(@) " sin " 20^(@) =(sqrt(3))/(2) (ii) " cos " 45^(@) " cos " 15^(@) - " sin " 45^(@) " sin " 15^(@) = (1)/(2) (iii) " cos " 75^(@) " cos " 15^(@) + " sin " 75^(@) " sin " 15^(2)= (1)/(2) (iv) " sin " 40^(@) " cos " 20^(@) " + cos " 40^(@) " sin " 20^(@) =(sqrt(3))/(2) (v) " cos " 130^(@) " cos " 40^(@) l + " sin " 130^(@) " sin " 40^(@) =0